Definition of "notochord" []

• A flexible rodlike structure that forms the main support of the body in the lowest chordates, such as the lancelet; a primitive backbone. (noun)
• A similar structure in embryos of higher vertebrates, from which the spinal column develops. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "For example, the notochord is a character that provides internal structural support and unites all members of the phylum Chordata or chordates, animals with notochords and pharyngeal arches, among other characteristics."
• "A notochord is a rope of nervous connection which branches into the trunk nerves of the body."
• "Thus the notochord is the necessary forerunner of the vertebral column, cartilage the precursor of bone."